Detachable coupling for electrical conductors



Sept. 5,-1 939. R. c. HOWELL.-

DETACHABLE COUPLING FOR ELECTRICAL CONDUCTORS Filed April 12, 1938 l lll IN VENTOR 2) 0- Howell BY 3M ATTORNEY Patented Sept. 5, 19 39 DETACHABLE COUPLING FOR CONDUCTORS ELECTRICAL,

Roy 0. Howell, Lakewood, Ohio Application April 12, 1938, Serial No. 201,543

6 Claims.

This invention relates to detachable couplings for electrical conductors particularly for conductor cables such as are employed to conduct current to portable, electrically operated machines such as welding machines.

This invention has for its object to provide a coupling by means of which successive lengths of conductor cable may be quickly and easily joined.

A further object is to provide a coupling for conducting elements of low resistance capable of carrying heavy currents without excessive heating, the conducting elements of the coupling members being firmly locked in contact with each other when the coupling members are joined together.

A further object is to provide a detachable coupling provided with conducting elements which are adapted to interlock and which have relatively large contacting areas which are kept clean by wiping action incident to the locking and inlocking of the-coupling.

A further object is to provide a detachable :oupling in which the interlocking connecting nembers of the coupling are of identical con- ;truction so that no selection is necessary in at aching to.conductors orin joining conductors .ogether, and the manufacture of a single article rnly is required.

A further object is to provide a conductor :oupling of the bayonet joint type in which conact is maintained by spring pressure and in IhlCh the elements are positively locked together vnd in which the elements may be quickly and asily attached or disconnected.

With the above and other objects in view, the ivention may be said to comprise the coupling shown in the accompanying drawing hereiafter described and particularly set forth in the ppended claims, together with such variations nd modifications thereof as will be apparent to me skilled in the art to which the invention apertains.

Reference should be had to the accompanying rawing forming a part of this specification, in hich:

Figure 1 is a side elevation showing two de- .ched coupling elements positioned for engageent by a relative axial movement;

Fig. 2 is an axial section through a pair of ined coupling members;

Fig. 3 is a fragmentary perspective view of the cking end of one of the coupling members; Fig. 4 is a fragmentary detail view showing the terlocking lugs in side elevation;

Fig. 5 is a section taken on the line indicated at 55 in Fig. 4.

In the accompanying drawing a coupling embodying the invention is illustrated which is composed of two identical coupling members indi- 5 cated by the reference character A. While the identity of the two coupling members is very de- 'sirable and convenient, it is to be understood that this feature is only one of several herein disclosed and claimed, and, while preferred, is not essential to the invention.

As illustrated in the accompanying drawing,

' the body of each coupling member A consists of a cylindrical block I which has an axial bore 2 opening to the end thereof which engages the mating coupling member. Withinthe bore 2 is mounted a pin 3 which has an enlarged head 4 slidable in a counterbore 5 which extends to the opposite end of the coupling member. The pin 3 is normally held in its outermost position by a compression coil spring 6 which is mounted between the head 4 of the pin and a plug 1 secured" Within the counterbore 5, The plug l is secured in the counterbore 5 inwardly of the end of the block i to provide a suitable socket to receive a conductor cable 3 which'is secured by suitable means to the block I, preferably by sweating or soldering. p The end of the blockl in which the bore 2 is provided is cut away on an axial plane to provide a semi-cylindrical projection 9. The inher face of the cylindrical projection 9 lies in a plane diametrically intersecting the bore 2 leaving a half bearing H) in said facefor guiding the pins 3 of the coupling members when joined. The projection 9 has a fiat end face H and a flat shoulder 12 is provided on the block 8 at the base of the cutaway portion. The projection 9 has a recess l3 cut in one side thereof adjacent the shoulder B2 to provide an overhanging locking lug M outwardly of the recess. The axial depth 5 of the recess is greater than that of the lug so that the recess H of one coupling member is adapted to receive the lug M of a mating coupling member when the members are fitted together and one, of the members is turned with respect to the other. At, its outer end the lug I4 is provided'with a inclined cam face l5 and adjacent the inner'end thereoi is provided on its inner face with a notch l6 providing a locking tooth l'l at the outer end of the lug.

The block l is mounted within an insulating sleeve l8 which covers the block I from the end thereof to which the'cable 8is attached to a point substantially midway between the inner and outer ends of the projection 9,

The portion of the sleeve extending beyond the shoulder It provides a semi-cylindrical socket to receive the semicylindrical projection 9 of a mating coupling member. A disk I9 of insulating material sur rounds the cable 8 and covers the end of the block I around the cable, the cable 8 being provided with an insulating covering 20 up to the outer face of the disk IS.

The pin 3 of each coupling member is normally held by the spring 3 in a position in which its outer end projects slightly more than half way to the end of the projection 9 so that when two of the coupling members are engaged one with the other and pressed together axially, the pins 3 are guided between the half bearings ll of the complementary projections 9 and are forced inwardly against the springs 6. When the couplings are joined the fiat end faces of the pin are pressed axially one against the other by the springs G. The pins 3 are of electrically conductive material such as copper or brass to provide a low resistance connection between the coupling members.

The blockl is also preferably composed of electrically conductive material particularly when the coupling is used in lines through which current of high amperage is passed. The block I may be readily formed from copper or brass bar stock by simple machining operations. V

In joining two of the coupling members, the members are moved axiallyinto engagement with the semi-cylindrical projections 9 thereof fitting over the pins: 3 andprojecting into the sockets formed within the sleeves I8. The pins 3 and sleeves I8 provideconcentric bearing surfaces and, since the locking lugs ll of the two coupling members are opposite the recesses [3, the coupling members may be turned, one relative to the other, to cause the lugs M to enter the recesses l3. The inclined cam faces I5 of the locking lugs I4 are opposed one to the other so that by grasping the sleeve I8 of the two coupling members and turning them in opposite directions one cam face I5 will ride over the other as the lugs I4 enter the recesses I3 pulling the coupling members together, forcing the pins 3 inwardly and compressing the springs 6. The tooth I! of one lug is thus caused to ride over the tooth ll of the other, whereupon the springs 6, which tend to force the coupling members apart, will cause the teeth I! to snap into the notches I6 thus locking the two coupling members against relative turning movement. The lugsll positively hold the coupling members against separation by relative axial movement, the locking teeth I1 prevent accidental relative rotation of the coupling elements which would free the lugs. As shown in Fig. l of the drawing, the inclined cam faces I5 of the locking lugs have inclinations such that when brought into engagement by a turning movement the cams engage first adjacent their inner edges so that when turning one of the coupling members upon the other there is a greater leverage on the engaging portions of the cam faces, the engagement between the cam faces being near the axis and at a greater distance from the surfaces of the sleeves I8 where the force is applied.

To disconnect two of the coupling elements, the

two coupling elements are gripped firmly and one is pressed axially toward the other compressing the springs 6 until the locking teeth I! are retracted from the notches Ii whereupon the coupling members may be turned in a direction to release the locking lugs ll. After the point of one of the locking teeth II has passed outwardly past the point of the other, the coupling members may be released and the cam faces l5 pressed together by the actions of the springs 6 will rotate the projections 9 to the position in which the two lugs I4 are clear of each other and the coupling members may be freely separated.

The insulating sleeve l8 may be any suitable insulating material secured in any suitable way to the blocks I. It has been found that an ex-v cellent union may be made between a metal block I and an insulating sleeve of fibrous material by knurling the surface of the metal block as shown in Fig, 4 and forcing the block into the sleeve after cutting away the interior of the sleeve slightly at one end to permit the block to be partially inserted.

When the'coupling members are joined together there is a slight gap between the ends of the sleeves I8 of the two coupling membersto permit the relative movement necessary to permit the teeth 11 to be engaged or disengaged. If it be desired to close this gap the sleeves may bemade of a length such that the ends thereof will be in engagement when the coupling members are locked together if the edge portions of the sleeves are sufiiciently elastic to permit the relative axial movement necessary for the locking operation. Such elasticity may be provided by making the edge portions of the sleeves of elastic rubber,

When the coupling members are joined together, a conductive connection between the cables-8 is made throughthe pins 3 and plugs I. When the blocks l are made of electrically conductive material, the locking lugs I4 which are held together under pressure provide contact members for the passage of current. Current passes from the block I of one coupling member to the block I of the other through the end faces of the pin 3 and through the bearing surfaces engaging the pins 3, and through the interengaging surfaces of the locking lugs. During the operation of making and breaking the coupling, the pins 3 are caused'to slide upon the bearing faces. The end faces of the pins are caused to turn upon each other while under pressure and the surfaces of the teeth I! are caused to slide upon each other so that these contacting surfaces are kept clean and current passes freely from one coupling member to theother.

By reason of the fact that the locking element: of the two members are of identical construction any coupling member may be joined with any other coupling member and no problem of selection is involved in attaching the coupling members to the cable ends by joining lengths of cable together. Also, the manufacture of the coupling is simplified because there is only one article 01 manufacture and a saving in replacement cost: is affected because of the fact that any couplim member will replace any other coupling member.

Furthermore, it is to be understood that thl particular form of apparatus shown and described, and the particular procedure set forth are presented for p rposesof explanation ant illustration and that various modifications c said apparatus and procedure can be made with out departing from my invention as defined ii the appended claims. a

What I claim is: v

1. A detachable coupling for electrical con ductors comprising two coupling members adapt ed to be connected'to eiectrical conductors an each having electrically conductive portion adapted to contact when said members are joined, each coupling member having an outer sleeve of insulating material and a locking mem-- ber fitting within the sleeve and attached thereto, said locking member having a shoulder at one side thereof spaced inwardly from an end of the sleeve and an axially extending projection at the opposite side thereof which projects past the end of the sleeve, whereby the coupling members may be assembled in axial alignment with the projection of each extending into the sleeve of the other, said projections each having a laterally extendirig locking lug spaced axially from its shoulder, said locking lugs being movable into axially overlapping relation by a relative turning movement of the coupling members when assembled in axial alignment, the opposed inner faces of said locking lugs being each provided with a projecting tooth, and resilient means tending to force said coupling members apart and serving to maintain axial pressure between the lugs to yieldingly hold the teeth thereof in engagement to lock the coupling members against relative turning movement.

2. A detachable coupling for electrical conductors comprising two coupling members each having a cylindrical contact member of conductive material, cut away at one end to provide each contact member with a shoulder and a substantially semi-cylindrical projection outwardly of the shoulder, each contact member 'having a sleeve of insulating material attached thereto and extending past its shoulder, whereby each coupling member is provided with a socket to receive the semi-cylindrical projection of the other, each projection having a recess in one side thereof adjacent the shoulder providing a locking lug overhanging the recess, the recesses being of sufllcient axial width to receive said lugs when said coupling members are interfltted and one is turned with respect to the other, each locking lug having an inwardlly projecting tooth adjacent its outer end, and a spring pressed member resisting axial movement of one coupling member into the other and acting to press one of the locking lugs against the other to retain the tooth of one behind the tooth of the other to lock the coupling members together. i

3. A coupling member which is adapted to interlock with an identical coupling member to provide a detachable connection comprising a cylindrical sleeve and a cylindrical block within said sleeve, said block having an axial cylindrical bore opening to one end and a counterbore opening to the other, a cylindrical pin which has a sliding fit in said bore the end of the block to which the bore extends being cut away along an axial plane to provide a semi-cylindrical projection extending past the end of the sleeve and providing a half bearing for said pin, said projection being undercut at one side to provide a projecting lug and a recess to receive the corresponding lug of an identically constructed coupling member, and a spring mounted in the counterbore and adapted to exert axial pressure upon said pin.

4. A coupling member which is adapted to interlock with an identical coupling member to provide adetachable electrical connection com prising a cylindrical insulating sleeve and a cylindrical electrically conductive block within said sleeve, said block having an axial bore opening to one end and a counterbore opening to the other, a pin slidably mounted in said bore, the end of the block to which the bore extends being cut away along an axial plane to provide a semicylindrical projection extending past the end of the insulating sleeve and providing a half bearing for said pin. said projection being undercut at one side to provide a projecting lug and a recess to receive the corresponding lug of an identically constructed coupling member, a plug secured in said counterbore and spaced from the end thereof to provide a conductor receiving socket, and a spring interposed between said plug and said pin.

5. A coupling member which is adapted to interlock with an identical coupling member to provide a detachable electrical connection comprising, a block of condutive material having a cylindrical portion which is cut away'at one side to provide a shoulder and a projection having an arcuate outer face and an inner face substantially in an axial plane, said projection having a recess in its axial face at one side thereof adjacent said shoulder, said recess having an axial depth of more than one-half the height of said projection so that the said recess provides a lug adapted to enter the corresponding recess 61' an identical coupling member, a spring pressed axially extending member mounted in said coupling member and projecting past said shoulder for engagement with a mating coupling element, and asleeve of insulating material mounted upon the cylindrical portion of said block and extending past the shoulder thereof to provide a socket to receive the projection of a mating coupling member. s

6. A coupling member which is adapted to interlock with a coupling member of identical construction to provide a detachable connection comprising a block having a bore opening to one end thereof, said block being formed at said end with a shoulder and a projection disposed wholly to one side of a plane axial with respect to the bore, said projection being undercut to provide a recess adjacent the shoulder 01' an axial width at least one-half the axial length of the projection and a locking lug outwardly of the recess adapted to enter the recess of an identical coupling member, said lug having a locking tooth on the side thereof toward said shoulder, a pin slidably mounted in said bore, and a spring acting upon said pin and normally projecting the pin past said shoulder a disttance greater than one- .half the length of said projection, whereby the the members interlocked by pressing one axially toward the other to aline the lug of each with the recess of the other and turning one relative to the other about the axis of the pins to engage the lugs. ROY C. HOWELL. 

